The present invention relates to gas turbine engines and, more particularly, to a method and apparatus for supporting a load carrying ring in such an engine.
In gas turbine engine development, it is often necessary to obtain various measurements of engine characteristics during engine operation. Such measurements require installation of various measurement devices, such as strain gauges and thermocouples, in the engine. Some of these devices must be coupled to rotating components or in rotating sections of such engines and require radio frequency transmitters for transmitting the collected data to appropriate monitoring stations. In at least some instances, the measurement devices are positioned adjacent an outer surface of the engine to provide accessibility, cooling and proximity to stationary components for antenna mounting. The measurement devices must be supported from centrifugal loading in a structure which is relatively light weight in order to minimize its effect on engine dynamics. The structure must be connected to some other rotating part of the engine and thus presents a problem of thermal and mechanical growth mismatch due to high speed rotation and heat generated by the engine turbine, i.e., the engine component and the telemetry support structure have different thermal and mechanical growth rates.
Another problem with positioning of telemetry devices within the gas turbine engine is that the devices must be supplied with cooling air to maintain their operating temperatures within predetermined limits. In general, most such telemetry devices are limited to about 180.degree. F. The air temperature within the engine between the engine turbine and the outer cowl may vary from 400.degree. to 600.degree. F. Accordingly, it is necessary to provide air from outside the engine for cooling the telemetry devices.
In other applications, a load carrying ring may be stationary but subjected to thermal conditions which cause the ring to "grow" at the rates different from the apparatus to which the ring is connected. Thus, the problem of supporting dead loads, i.e., loads which do not provide structural support, extends to both rotating and non-rotating carrier rings.